Treatment of animal skins and pelts



Patented Feb. 9, 1932 UNITED STATES PATENT OFFICE ILHELM 'SAILER, or

SCHWAAN, GERMANY, ASSIGINOR TO THE MEAD RESEARCH EN- GINEERING COMPANY, OF DAYTON, OHIO TREATMENT OF ANIMAL SKINS AND PEI-TS No Drawing; Application filed December I2, 1929, Serial No. 413,686, and in Germany April 25, 1929.

The present invention relates to the treatment of animal skins and pelts.

The employment for tanning purposes, of sulphite cellulose liquor andlignin sulphonic acid and of their chlorination and esterification products is known.

These processes are only partially satisfactory however. I have found by experiments that, in working up skins and pelts to goodquality leathers novel tanning efiects can be obtained if, for tanning purposes, use is made of spent liquor from the manufacture of sulphite cellulose, or lignin sulphonic acid, which has been treated with hydrogen peroxide andhas subsequently been acted upon by chlorine or bromine, or both halogens together.

Instead of hydrogen peroxide,corresponding solutions of compounds capable of liberating oxygen, such as .perborates, persulphates andthe like, may be used.

In the place of spent sulphite cellulose liquor or lignin sulphonic acid, use may be made of natural tanning agents, or mixtures of any'of these substances with or without further admixture of phenols, cresols or similar compounds of the aromatic series,

for instance quinones or such naphthol and i anthracene compounds which contain one or drogen,

more OH groups, such as polyphenols and the like,.these compounds or their mixtures being persalts or the like and halogens. Instead of spent sulphite cellulose liquors, mixtures of such liquors and natural tanning substances maybe used. It is also possible to use natural tanning substances alone. To these. substances hydrogen peroxide or solutions of compounds capable of liberating oxygen may be used and simultaneously or subsequently chlorine or bromine or both halogens together may be allowed to act upon the mixture. v

It'is furtherpossible to use, instead of natural tanning substances, mixtures of same with the above named phenols, cresols or similar compounds of the aromatic series.

If reaction products of this kind arediluted with water and animal skins without hair, hides or pelts are tanned therewith, a very port.

also subjected to treatment with hynovel effect not hitherto known and of pronounced technical importance is obtained.

The depilated skins and the like, previously treated in this way, can be worked up in the shortest possible time to a leather, which possesses the advantages of a leather which has -been pittanned for months, if they are subsequently finishtanned in a known manprocess is of very great economic The present process can also be used with advantage for preliminarily tanning pelts, since these latter can easily be depilated subsequently without any difficulty with'known liming agents, leather; This has the advantage that such preliminarily tanned pelts can be shipped a long distance without spoiling during trans- I Ewdmple 150 kgs. of thickened spent sulphite cellulose liquor, lignin sulphonic acid or tanning extracts are treated with about 20 kgs. hydrogen peroxide (30%) or also with sultable and Worked up further to solutions of compounds capable of liberating oxygen, such as perborates, persulphates and the like. Chlorine or bromine or both halogens are 'then added to this mixture in such quantities or proportions that the reaction product absorbs about 6 to 10%. The quantity or proportions of chlorine or bromine be selected as desired, accordcan, however,

or strong tann ng efing-to whether a weak feet is desired. 6O kgs. of the above reaction product are diluted with about 100 kgs. water and can then be used for the preliminary tanning of pelts, hides or skins.

into consideration the tions of the substance i and pelts,

A and pelts, the hides After the hides have been penetrated to a sufficient extent, they are finished-tanned with vegetable tanning baths or merely partially tanned with the latter and then finish tanned with known chromium compounds, for instance with basic chromium sulphate solution.

It is evident that use may also be, made of dilute spent sulphite cellulose liquor, and also of dilute tanning extracts or mixtures thereof.

In that case it is merely necessary to take quantity or proporthe halogens.

I claim I 1-. A process of pre-tanning animal hides and pelts, comprising the step of pre-tanning the hides with a halogen reaction product obtained by bringing sulphite cellulose liquor into reaction with hydrogen peroxide and then halogenating. 2. A process of pre-tanning animal hides comprising the step of pre-tanning the hides with a halogen reaction product obtained by bringing sulphite cellulose liquor into reaction with an oxygen liberating substance of the class consisting of'peroxides, perborates and persulfates of alkali and then halogenating. v

3. A process of pre-tanning' animal hides comprising the step of pro-tanning with a spent tanning liquor to which has been added the halogenated reaction product obtained by acting upon sulphite cellulose liquor with a member of the class consisting of hydrogen peroxide, alkali peroxide. alkali perborate and alkali persulfate and then halogenating.

4. A process of tanning animal hides and pelts, comprising the steps of pro-tanning the hides with a halogenated reaction product obtained by reacting upon sulphite cellulose liquor with a member of the class consisting of hydrogen peroxide, alkali peroxide, alkali perborate and alkali persulfate and halogenating such reaction product, and then finish-tanning the hides with a natural tanning substance. I

5. As a new product, an animal hide which has been pre-tanned with a halogenated re-' action product obtained by reacting upon sulphite cellulose waste liquor with a member of the class consisting of hydrogen peroxide,

alkali eroxide, alkali perborate and alkali persul ate and-:halogenating such reaction product.

6 As a new product, an animal hide which has been subjected to the respective steps of pie-tanning and finish-tanning, ning step consisting in wetting the hide with the halogenated reaction, product obtained by reacting upon sulphite cellulose waste liquor with a member of the class consisting of hydrogen peroxide, alkali peroxide, alkali pergiving ofI" oxygen and the pre-tan- 1 my hand.

WILHELM SAILER. 

